Switched to air lock, bubbles stopped....hmm

[teleplucker]

I finished my second one gallon batch last weekend. I used a blow off tube since I had overflow on the first batch....this batch overflowed into the tube too. Initially, I was getting bubbles through the blow off tube every 4-5 seconds, then the krausen diminished and it slowed to 7-9 seconds. Since the tube was a PITA to clean the first time, I wanted to get the airlock on as soon as it seemed reasonable and before the overflow dried. However, since I have put the airlock on, there are no bubbles. Why?

I'm not worried. If there is one thing I've learned in reading this forum, it's don't worry. I'm just wondering why the bubbling stopped (or potential reasons). I assume it has something to do with air displacing CO2 when I switched to the air lock, but I'm a noob, so, who knows?

 

[stonecutter2]

Are you using a stopper with a hole on the 1 gallon jug, or one of those plastic screw on type tops with a hole in it.

Also, what kind of airlock is it. A 3-piece, or the kind that's like S-shaped (bubbler).

 

[stonecutter2]

If you're using a rubber stopper with a hole in it, that is somewhat mysterious as there shouldn't be any air leak except through your airlock. That is, unless fermentation is 100% done, in which case you probably won't have any more bubbles. Even so, you should get occasional bubbles (very randomly) due to pressure changes.

If you're using a plastic top that screws on, I've had a couple that were pretty air tight, but 1 of mine leaks terribly, no matter how tight I screw it down. There is no gasket on these, so a bad plastic shaping on the topper will mean air gaps. Your beer might be letting off co2, but your airlock creates resistance to letting out gas (the liquid seals the container, until the pressure is enough to make it bubble). If the pressure is great enough to leak out of the topper, it won't build up enough to make the bubbler/airlock bubble. You're still letting off co2, but through the leaks in your topper, not through your airlock.

My advice is this:
First, try reducing the amount of liquid you have in your airlock. That will create a bit less resistance, and you might see some bubble action.

Second, if you have the screw on plastic toppers, try finding a rubber gasket/washer that will fit inside of them. I'm going to do that with mine, to create a really good seal. The gaskets can be removed for cleaning/sanitizing, too.

 

[teleplucker]

The airlock is a three piece. The stopper is a plastic screw on cap. I bought a Brooklyn Brew Shop kit initially, so I'm using their jug/stopper/airlock. The leak explanation would make sense. With the blow off tube, it's possible that it fits tighter....I don't think so, but it is possible. But, there is definitely less resistance with the blow off tube. With the airlock, the CO2 has to go through a smaller opening and then exert more pressure to create bubbles.

 

[stonecutter2]

The airlock is a three piece. The stopper is a plastic screw on cap. I bought a Brooklyn Brew Shop kit initially, so I'm using their jug/stopper/airlock. The leak explanation would make sense. With the blow off tube, it's possible that it fits tighter....I don't think so, but it is possible. But, there is definitely less resistance with the blow off tube. With the airlock, the CO2 has to go through a smaller opening and then exert more pressure to create bubbles.

I would try to reduce the amount of liquid in the airlock and see if it makes it start bubbling.

Do make sure that the plastic cap is screwed on as tight as you can get it. Purely theoretical, but I've wondered if even a rubber band wrapped around the gap between cap and bottle would seal it enough to force air through the airlock.

Like I said, I have 1 cap out of 3 that leaks...and I've pondered how to solve this very problem myself

In the end, it's not a HUGE deal, but it is a bit weird. The CO2 is escaping, just not through the airlock. And the leak in the cap is well covered so nothing bad should be able to get in, but air can get out.